int main()
{
  float x, y;
  x = 1.0 / 0.0;
  y = x / x;
  printf("%f %f\n", x, y);
  printf("%x %x\n", x, y);
  if (y == y) printf("%s\n", "nan is equal to itself");
  else printf("%s\n", "nan is not equal to itself");
}